The invention pertains to a device for temperature control of coating mediums used in printing machines.
In applicator systems for printing presses, e.g., in coating systems, it is known to regulate the viscosity of the coating medium by means of temperature control. Temperature control can be used to regulate the processability of coating media for different types of media and for different methods of application. This can expand the processing range of such an applicator system.
A known device for coating surfaces in a printing process is disclosed in U.S. Pat. No. 5,520,739 A. This reference indicates that a coating composition for different systems can be supplied from a single storage container for the feeding of coating compositions to printing processes. Each device for supplying the coating composition is described as a reactor vessel, in which the temperature, and thus also the viscosity, of the coating composition can be influenced. For this purpose, there is a heat exchanger and a temperature sensor, as well as a viscometer for determining the viscosity of the coating composition in the reactor vessel.
The described device has the disadvantage that the coating composition can only be affected or controlled before the actual printing process or coating process. On the way between the reactor vessel and the printing process, however, the physical properties of the coating composition can change.
Another disadvantage of the above described device is that not all of the processing sequences can be affected by the processing sequences of temperature control. It is commonly necessary for there to be processing sequences for the rinsing or cleaning of the applicator system and the elements contained therein that transport the coating composition in order to prevent permanent contamination through hardening of the coating composition. Here, it is also advantageous to control the temperature of the cleaning process. This is not possible with the described device.
It is an object invention is to provide a coating system for a printing press in which the temperature of the coating medium is more reliably controlled in close proximity to the printing process and in which the cleaning process following a coating operation also may be temperature controlled for optimum processing.
In carrying out the invention, it is advantageous if the temperature control of the coating composition is not performed in a storage container, but instead directly at the place of processing. Suitable positions or locations for temperature control include a chamber wiper, a screen roller connected to the chamber wiper, or, if necessary, a metering roller connected to the screen roller or to a comparable applicator roller. It also is advantageous if the form cylinder transferring the coating layer or the coating medium is a device susceptible temperature control. In one suitable form of the invention, a heat exchanger is provided within each roller or chamber wiper. In another form of the invention, the temperature is detected at each element transmitting the coating medium.
In carrying out the invention, it is advantageous if the temperature control of the coating composition is no longer performed in a storage container, but instead directly at the place of processing. Suitable positions for temperature control are a chamber wiper, a screen roller connected to the chamber wiper, or, if necessary, a metering roller connected to the screen roller or to a comparable applicator roller. It is also advantageous if the form cylinder transferring the coating layer or the coating medium is realized as a device for temperature control. In a suitable form, there can be a heat exchanger within each roller or chamber wiper. In an additional suitable form, the temperature is detected at each element transmitting the coating medium.